I think that's because memories really are highly compressed, with the average complex memory (of a grand day out, for example) being compressed into at most a paragraph of text's worth of information. Everything else is made up of context.
For example, having no photographic memory, I can remember the general "feel" of the innards of an antique shortwave receiver I used to have as a kid. But almost all of that is context. I know what canned octal base vacuum tubes and big tuning capacitors look like, what sort of components were in the big band selector "sled" (for geeks: This was an NC2-40D) and so on. So I can "zoom in" on the coarse memory by just filling in details that are generic, not specific. And these details may be from different sources than the original memory too.
And so the brain needs to remember - if one is not faceblind, which in fact I am - just the overall geometry of someone's face, and all the other stuff can be filled in as needed (how they look when they smile or are anxious etc.) Compression, compression. We have a lot to learn from nature. Note that a faceblind person does this too, of course - just not with a geometrically exact visualization of that person's face, just one with the correct "feel".
And that's also why synthetic memories can be formed so easily. You really don't have to insert much. The brain infers the rest as needed.
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I think that's because memories really are highly compressed, with the average complex memory (of a grand day out, for example) being compressed into at most a paragraph of text's worth of information. Everything else is made up of context.
For example, having no photographic memory, I can remember the general "feel" of the innards of an antique shortwave receiver I used to have as a kid. But almost all of that is context. I know what canned octal base vacuum tubes and big tuning capacitors look like, what sort of components were in the big band selector "sled" (for geeks: This was an NC2-40D) and so on. So I can "zoom in" on the coarse memory by just filling in details that are generic, not specific. And these details may be from different sources than the original memory too.
And so the brain needs to remember - if one is not faceblind, which in fact I am - just the overall geometry of someone's face, and all the other stuff can be filled in as needed (how they look when they smile or are anxious etc.) Compression, compression. We have a lot to learn from nature. Note that a faceblind person does this too, of course - just not with a geometrically exact visualization of that person's face, just one with the correct "feel".
And that's also why synthetic memories can be formed so easily. You really don't have to insert much. The brain infers the rest as needed.